Attachment device



AWT 297 2.924.

S. MCCLATCHEE ATTACHMENT D .EVIGE l Filed March 2l. 19l9- Imi/e7@ Patented apn 29, 1924.

tl lll l Ml raises STANLEY MCCLATCHIF, 0F GAMBE-LEGE, MASSACHUSETTS, ASSIGNOR TO BENJAMIN ELECTRC lTANUFACTURNC-g CGIPANY, OF CHICAGO'I ILLINOS, A CORPORATON OF ILLINOIS.

ATTACHMENT neuron.`r

Application mediteren 21, 1919. sez-iai no. 284,113.

To all wiz/m 'it may @0n-cern.'

Be it known that l, STANLEY MoCLAToI-rin, a citizen of the United States of America, and resident of Cambridge, in the county of Middlesex and State of Massa chusetts, have invented new and useful Improvements in Attachment Devices7 of which the following is a specification@ My invention relates to improvements in the construction of swivel attachment plugs.

Attachment plugs of the class to 'which the present invention relates usually comprise an inner body or core of insulation material, an outer metallic shell which is adapted to connect one side of the cord circuit to the threaded portion rof thesoclet, a handle or linger-piece for rotating this shelly a cap of insulation material adapted to close the rearward end of the plug eX- cent for a central opening for the cord, a central contact adapted to connect the other side of the cord circuit to the central terminal of the socket. means for attaching the central contact to the latter side of the cord circuit, a sliding` contact for connecting the former side of the cord circuit to said metallic shell, means to limit the movement the swivel shell relativelyto the core, and means for binding the two limiting means together. Attachment plugs are valso cominoiny provided with means -for preventingr 'the cord from pulling out of the plug and `ith means usually comprising a coil of wire surrounding a short length of the cord at entrance to the plug for protecting the cord against excessive wear at this point. My invention includesr a. simp-liied structure and arrangement fory these various parts. *i

li'hile the invention in its various aspects is adapted to many applications and molifiy cations, l. shall describe infor the purpose.

o1" i-etting forth the rarious features involved, with reference to the preferred emhmliinent shown in ilne accompanying draw ings, in whic Figure 'l is a. side elevation vof the at-` .aelnnent plug7 portions of the handle being broken away; f

Figure is a side elevation of the plug provided with a modified handle;

yward end of the screw 9.

about the core.

Figure 3 is a front elevation of the rearward part of the plug core hereinafter referred to;

Figure l is central longitudinal section on line 1 -l of Fig. l, on an enlarged scale; and c Figure V5 is a transverse section on line 5 of Fig. 4f.

The particular embodiment of the invention chosen for kthe purpose of illustration comprises in general a body or core divided transversely into 1 forward and rearward parte l and 2, a metallic shell 3 rotatable around the body or core, a cap l closing the rearward end of the metallic shell except for a central opening to receive the electric cordy 57 and a handle` which projects behind the plugand which may be flexibly entended as shown in F ig. 1, or which may eX- y n u ltend only` a short distance behind the plug 'position` or other suitable insulation material, and the two parts thereof are provided with axial openings? and 8 to receive means for attaching the two parts together. The attachment means shown in the drawings comprises ay screw 9 extending forwardly through the opening 7 in the part 2, and a nut having tubular -portion extending` rearwardly through the axial opening 8 in the forward part l threading over the for- The screw 9 is provided with a flange ll. on one side thereof adaptedl to prevent the screw from being drawn forwardly tlnfongh the opening 7 and adapted to Contact with one of the terminals of the cord 5 as will herein-- after be explained. Thenut l() is provided with a flanged portionr overhanging the forward face of the part l. which adapted to form the central terminal of the plug 3 is athreaded metallic shell swivellino The portion Il pr erably `made of composition moulded onto the shell 3. The forward end of the shell 3 is turned' inwardly to forni a flange 1B which7 adapted to extend into the annular space between the forward and rearward parts 'l and 2 of the core of the plug. The opposing faces 'of the two parts of the core man 1..

LvKal.

are so shaped that when the two parts are connected together by the screw 9 and nut space will beV provided just wide enough to permit the flange 13 to turn freelythere-V in without permitting any considerable lateral movement.

The rearward part 2 of the core is made fof a' size such that vit is'adapted to be inthe forward part 1 is centered by theV pro-V jection 15, the rearward part 2 is also centered when attached to the forwardpart by means of the screw 9 and nut 10.

The two conductors of the cord are preferably led-.finto the plug and connected to the two terminals thereof in the following manner: Three longitudinal openings 16, 1 7 and 18 are provided in the rearward part 2 ofthe core, andV in the forward face of the part 2 an annular groove 19 is provided concentrically with the opening 7Y-throughout substantially 180O on thereccentric side of the core. The recess 20 provided in the forfward face o1"- the part 2 between the openings 16 and 17. and a similarrecess 21 is provided between the opening 18 andthe recess V 22 connecting the recess 21 with the.

`shown at 23 in Fig. Il. The other conductor of the electric cord is extended forwardly through the opening 18, thenceA laterally7 1 along the recess 21. thence radially7 through above described, but it is also Vmade'to cor-y the recess 22, and thence around in the .,eroove 19. The groove 19 is not only formed concentrically with the axis of the core as respond with the cylindrical projection 15 mounted on the forward part 1 of the core. The projection 15 is covered with a channel- Vshaped ring 24.1; of conducting material and is adapted to extend into the groove 19. and clamp the end of the last mentioned conductor against theV bottom ofv the groove, as -well as to hold the core central.

The ring 24: covering the cylindrical. ex-V tension 15 is also provided with a flange adapted to engage the forward side ofthe flange 13 of the shelllj, wherebyV the last vmentioned conductor is connected to the l cessible sockets.

shell 3 rthrough the medium of member 15 and flange 13. The extension 15 is preferably molded into the ring 2l when the part 1 is formed'of composition material. As will be apparent from the above description the first mentioned conductor is connected to the nut 10, which forms the. other terminal of the, plugl throughy themedium of the flange 11 and screw 9.

ln order to provide a better contact between the end of the conductor disposed in groove 19 and the shell 3, l preferably line the groove 19 with a pressed metal member 26 which covers the base of the groove and both the inner and outer sides of the `groove. The portion 25 covering the inner side of the groove is extended around the plug in the form cfa continuous ring, the inner side of the groovevand the aforesaid ring preferably being tapered as shown in Figs.A 3 and 4 so that the end of the projection 15 will'V bear thereagainst. The lining 26 is preferably provided with Aan exterior flange 27 cov.- Y

ering the eccentric portion of the-rearward part 2 of the'core and extending substantially from point 28 to point 29 in the shape ofA a crescent as shown in Fig. 3. This metallic flange forms the bearing surface against the rearward face of the flange 13.

,illlhile the features of my invention lieretofore described are novel andV usef-.il per they are of particular importance in the present invention inrthat they mutually contribute to the most satisfactory application of the principal feature of my invention whichy will vnow be described;V

The construction shown comprises an ex-V tension from the rear of the swivel member by means of which the plug may be easily and quickly attached or detached in inac- The essential characteristic of this extension is that it has a relatively small diameter to facilitate rotation of the swivel member. Howeven,y the extension may be relatively long as Shown'in Fig. 1 or it may be comparatively short as shown in Fig. 2. lv/loreover. it may be either flexible as shown in Fig. 1 or rigid as shown in Fig. 2. lhen made rigid it is preferably formed as au integral tubular extension on the swivel member as shown in Fig. V2.

When lthe aforesaid extension is made flexible it is preferably constructed as shown in Figs. 1 and e. Asshown in these figures the extension 6 comprises three layers of spirallvv wound wire.v The wire in cach layer is preferably closely wound and sucso that when the coils are placed inside of veach other the inner coils expand snugly C- scribed the wire forming the outer coil is preferably both heavier and wider than thek The ends of wire forming the inner coils. the wire of the respective layers or coils are secured together and this may be done by molding the ends of the wires intol the cap 4 and the finger piece 80 respectively, the cap 4 and finger piece SO preferably being formed of composition material suoli as ordinarily employed for electrical insulation. In order to securely anchor the ends of the wires to the cap 4 and linger piece 30 the ends of the wires are preferably bent outwardly so as to be firmly embedded in the composition material. Thus in Fig. 5 the ends 31, 32 and 83 of the outer, intermediate and inner coils, respectively, are bent outwardly and are thus lirmly embedded in the cap 4. The opposite ends of the wires are similarly anchored in the finger piecel 30. The essential feature of the extension 6 fis that the successive layers are wound in opposite directions. Thus when employing three layers' of wire the inner and outer layers would be wound in the same direction and the intermediate layer would be wound in the opposite direction as shown in Fig. 1.

By constructing the extension 6 as "aforesaid, it is quite flexible and vet will resist torsional stress in either direction. Indeed,

this construction affords a handle which, while readily fiexible, cannot be appreciably twisted, so that rotary forces applied 'in either direction will produce substantially no give in the member.

The essential feature contributing to this result is the opposite winding of the successive layers. Then so wound a force applied in the direction tending to unwind the outer layer will tend to wind the central layer still tighter and to unwind the inner layer. The tendency for the inner layer to unwind causes it to expand against the intermediate layer and the tendency ofthe intermediate layer to wind still tighter causes it to contract against the inner layer. Thus the inner and intermediate layers buck against 'each other. lfihen a force is applied to the iinger piece tending to wind the outer layer/ still tighter the intermediate layer tends' to unwind and the inside layer tends to .wind still tighter. -In this case the outer layer tends to contract against the intermediate layer and the intermediate layer tends to`- expand against the outer layer so that the.

opposition of the outer and intermediate layers-prevents rotation of the finger piece relative to` the cap 4. l

It is desirable that the wire be flat in order to prevent the turns of the respective layersy from 'wedging through the turns of the adjacent layers in manipulating the handle; and byy making the inner layers narrower andlighter than the outer layers both flexibility and resiliency of the handle are attained in maximumdegree.

The parts of the'swivel member compris ing the shell 3,cap 4, extension 6 and linger piece 30, are permanently connected together to form a single kpart. In assembling the de` vice lthe cord 5 is `passed through the hollow eXtensionf, one'offlthey wires of the cord is passed through the openings 16 and 17`and `then positionedk under the flange 11of the screw 9, the other wire is passed through thef opening '18 and the end of the wire is placed in the groove 19, the part 2 of the core is then `rinsertedfinto the shell' 8 through'- the open forward end thereof, the part 1 ofthe forward face ofthe part :2, and the nut 10 is then threaded on to. the end ofthe screw 9 to secure the parts in the position shown in Fig. 1.

1 core with the metallic ring 15 permanently@ 'secured thereto is placed in position over the the conductors lying in the .recesses when the part 1 is secured in position, thereby assisting in preventing the wires from being pulled out of the plug by forces applied to the cord. However, the principal agencies preventing the cords4 from pulling out comprise .the tortuous channels through which the conductors are passed, the channel for oneconductorinvolving a 180 turn in passing from the opening 17 to the opening 16, and the passagel for the other cord involving a 90C turn in passing from the opening 18`to the recess 21 and involving a 180'3 turn in passing the yrecess 21 to the slot 19. f r

It will b e noted that the means comprising screw k9 and nut 10k not only serve to secure the two parts of the core together, but also toy form the central terminal of the plug inasmuch as they are adapted y'to connect with one conductor of the cord at the rear end'and inasmuch as it projects from the forward end ofthe plug at its forward end. The interfitting groove 19 and ring 15 serve not only-to center the `core in the shell and thereby prevent the core from pulling out of theshell, but these parts also serve'as attachment means for one oftheconductors to the shell 3 through the sliding connection between the flanges '13 Owing to the fact thatpart 2 of the body or core bears against the flange 13 only on one side of the plug, rearward forces on the shell tend to swing the Vcore transversely. Thisl is prevented by having the portion 'of the part 2V bear against the inner periphery'of the swivel member'on the side opposite to the projection engaging behind the flange or shoulder 13.V I claim: K Y l. In an attachment plug, a swivel member, two members adapted to position said swivelmember, means for securing said two members together, and means including a groove in one sideY of said two members and a corresponding projection in the other of said two members for clamping a conductor therebetween in electrical contact with one terminal of the plug. 2. A swivel attachment plug comprising an insulation body and a metallic shell rotatable around the body, said body being divided'transversely into forward and rear- 1 ward parts, means for securing: the parts together with an arcuate space therebetween, said shell having a flange adapted. to extend linto said' arcuate space to restrain axial movement vof the shell relatively to the body, the' rearward part of the body having a diameter sufiiciently small to permit it to berinsertedv into the'shell through the forward open end thereof and'having an eccentric portion adapted to. extend behind said flange when the rearward partis centered in the shell, and the forward part' of the body having a. portion adapted to cooperate with said flange to center both parts of the body when connected together by said means. Y

3. A swivel attachment plug. comprisingV an insulation body' and a metallic shell rodiameter sufficiently small to permit it to be' inserted into the shell throughy the forward opening and having anV eccentric portion adapted to extend behind said flange when the'rearward partis vcentered in; the shell,

' and the rearward part of the bodyv having a-circular groove its forward face adapted to receive-the end of anrelectrlcal conductor, the circular groove being concentricV 'with the axis of the shell and lying'justwithin the inner periphery 'of said flange when. theirearward part of the rbody is centered, and the forward part ofthe body having a cylindrical metallic portion adapted to lit throughY 'said flange; and extend'into which a ing the'body, the bodyhaving two longV Y tudinal openings therein through one of conductor may extend forwardly` and through the other of which the c'on- Y ductcr may extend rearwardly, an an axial conductor member for connecting with the end ofV said conductor beyond the parts of said conductor which lie in said openings at the'rear of the body, said member projecting from the forward face of the plug so as to 'contact with the central terminal of the socket into which the plug is inserted.

An attachment plug comprising an insulation body and a' metallic shell surrounding the body, the body being transversely divided kinto a forward anda rearward part,

lthe vrearward part having a longitudinal ,openingy therethrough and a concentric groove in its forward'face so arranged that a conductor may be extending through said opening and have its end disposed in said groove, the forward part having a concentricr metallic ring on its rearward face u adapted to extend into said groove and bear tightly against the end of vthev conductor when the two parts of the bodyY are connected together and to connect said conductor to said shell, and a metallic member extending through axial openings.. in said parts to secure said two parts together, said metallic member being adapted to connect with the other conductor at its rearward end and projecting from the forward end of the body to contact with the central terminal of the socket. l Y

6. An attachment plug comprising a twopart insulating base, wiring terminals mounted thereon, a center contact mounted thereon, and a screw-shell swiveled thereon, said screw-shell having an inwardly extending annular flange, one Yof said base parts being provided with an abutment rigid with respectthereto,l which is moved past said Vannular shoulder in assembly, and laterally to engage said shoulder to position said swivel shell.

7. VAn attachment plug comprising a twopart insulating base, wiring terminals mounted thereon, a center contact mounted thereon, and "a screw-shell swivel'ed thereon, said` screw-shell having an inwardly extendingannular flange, one of said base parts being provided with an abutment rigid with respectY thereto, which is 'moved past said annular shoulder in assembly, and laterally to engage saidv shoulder to position said swivel shell, the other of said base parts being provided with means for centering it with respect to said swivel shell contact, and means for securing said base parts together to hold said irst base part centered.

8. An attachment plug comprising atwopart insulating base, wiring terminals mounted thereon, a center contact mounted thereon, and a screw-shell swiveled thereon, said screw-shell having an inwardly extending annular flange, one of said base parts being provided with an abutment rigid with respect thereto, which is moved past said annular shoulder in assembly, and laterally to engage said shoulder to position said swivel shell, and means for holding said base parts centered to prevent disengagement from said shoulder.

9. An attachment plug comprising an insulating base, wiring terminals mounted thereon, and a screw-shell swiveled with respect thereto, said screw-shell having an inwardly extending annular flange, and said base being provided with an abutment rigid with respect thereto which is moved'past said annular shoulder in assembly and laterally to engage said shoulder to position said swivel shell, and means for centering said insulating base to prevent its disengagement from said swivel shell.

10. An attachment plug comprising a two-part insulating base, wiring terminals mounted thereon, a center contact mounted thereon, and a screw-shell swiveled thereon, said screw-shell having an inwardly extend- 'lng annular flange, one of said base parts being provided with an abutment rigid with respect thereto, which is moved past said annular shoulder in assembly and laterally to engage said shoulder to position said swivel shell, said flange being at the entering end of said screw-shell, and means for securing said base parts together to hold said iirst base parts centered.

11. A swivel shell attachment plug comprising a two part insulating base to which the wires are secured, a swivel shell contact swivelled on said base and having an inwardly extending flange at its entering end held in place between the two parts of said base and means forming a center contact and wiring terminal therefor comprising a screw extending through said base parts and having a clamping portion for clamping the bai-ed end of the Wire and a nut threaded on said screw and forming a center contact, said nut and screw serving to hold the two base parts together.

12. A swivel shell attachment plug comprising a two part insulating base to which the wires are secured, a swivel shell contact swivelled on said base and having an inwardly extending flange at its entering end held in place between the two parts of said base, and means Jr'or drawing said base parts together to clamp the bared ends of a wire therebetween, comprising a screw extending axially through said base parts.

Signed by meat Boston, Massachusetts, this 19th day of March, 1919.

STANLEY MCCLATCHIE. 

